An MH334 was gifted to me by the community but unfortunately life has been getting in the way of my posting its full review. It's something I've been working on (on and off) for months. Hopefully it'll be finished and posted next month.

easy man , take your time , hope these things are not taking a toll on you , i know its quiet stressful , huge archive of reviews , responding to everyone , job and commitments are like living another life with in this small life , take your time , just take it easy :) .

Since I don't think starting a new thread would bring anything useful:Which IEM do you consider the most extended (bandwidth) of all of the universals?
Would any of these be suitable for deep fit and have slim build an/or narrow nozzle, preferably working well with foam?

I would think that it's a bit weird to ask that. The high frequencies are relatively easy to reproduce, so it would only be a question of how low the bass extents.
While bass extension of IEM's is definitely sub-optimal (compared to full sized headphones, or especially sub woofers), a lot of IEM's can still extent pretty far. Not that it really matters all that much, since our hearing is insensitive to low bass notes in any case.

You'd be suprised, most IEMs end around 18 kHz and roll off even earlier.

There are a bunch of IEMs that reach 20 Hz indeed with plenty of power, but the only ones I've tried that reach all the way up were SE-5 Reference custom and Hifiman RE-272 (never again, hardening cable went brittle and broke by the earpiece - also it's not suitable for deep fit).

You'd be suprised, most IEMs end around 18 kHz and roll off even earlier.
There are a bunch of IEMs that reach 20 Hz indeed with plenty of power, but the only ones I've tried that reach all the way up were SE-5 Reference custom and Hifiman RE-272 (never again, hardening cable went brittle and broke by the earpiece - also it's not suitable for deep fit).

So what if it rolls off at 18kHz?
Those frequencies are pretty useless, if we can hear them at all.

With small drivers reaching all the way down to 20Hz is not really necessary either. Those are frequencies that you feel much more than that you hear them. And there is no way you're gonna feel them with such a small driver.

Imo decent extension from 40-16kHz should be plenty for an IEM.
You should be worrying more about other sound quality factors more than bandwith, if you ask me.

Wanting deep extension is completely fine with me, but in my personal opinion other factors are simply more important.

No it doesn't.
Not to be snobbish, but I have seriously studied a university text book on psychoacoustics, so I should know.

>16kHz information is identifiable, and does add something to the overall timbre of the sound (though very subtle). However, removing it wouldn't change the fidelity. It would just make it sound 'different', with the listener having difficulty pointing out just exactly what is different.

So what if it rolls off at 18kHz?
Those frequencies are pretty useless, if we can hear them at all.
With small drivers reaching all the way down to 20Hz is not really necessary either. Those are frequencies that you feel much more than that you hear them. And there is no way you're gonna feel them with such a small driver.
Imo decent extension from 40-16kHz should be plenty for an IEM.
You should be worrying more about other sound quality factors more than bandwith, if you ask me.
Wanting deep extension is completely fine with me, but in my personal opinion other factors are simply more important.

I can hear and feel it just fine down at 15Hz (or 12Hz for that matter) with my IEMs (Philips SHE3580)

Have you actually tested the extension on the two ends of your headphones with something like Sinegen?

No it doesn't.
Not to be snobbish, but I have seriously studied a university text book on psychoacoustics, so I should know.
>16kHz information is identifiable, and does add something to the overall timbre of the sound (though very subtle). However, removing it wouldn't change the fidelity. It would just make it sound 'different', with the listener having difficulty pointing out just exactly what is different.

Clearly astral has superior hearing ability and a greater knowledge than most normal people so do not dis-respect him. He is the dolphin man.